Power operated rotary knives are widely used in meat processing facilities for meat cutting and trimming operations. Power operated rotary knives also have application in a variety of other industries where cutting and/or trimming operations need to be performed quickly and with less effort than would be the case if traditional manual cutting or trimming tools were used, e.g., long knives, scissors, nippers, etc. By way of example, power operated rotary knives may be effectively utilized for such diverse tasks as taxidermy; cutting and trimming of elastomeric or urethane foam for a variety of applications including vehicle seats; and tissue removal or debriding in connection with medical/surgical procedures and/or tissue recovery from a body of a human or animal donor.
Power operated rotary knives typically include a head assembly and an elongated handle assembly releasably affixed to the head assembly. The handle assembly extends along a longitudinal axis and includes a hand piece having a gripping surface to be grasped by an operator or user to manipulate the power operated rotary knife. The handle assembly may include a central core or other attachment structure to releasably attach the handle assembly to the head assembly.
The head assembly includes an annular blade housing and an annular rotary knife blade supported for rotation by the blade housing. The annular rotary blade of conventional power operated rotary knives is typically rotated by a drive assembly which include a flexible shaft drive assembly extending through an opening in the handle assembly. The shaft drive assembly engages and rotates a drive train, such as, for example, a pinion gear supported by the head assembly. The flexible shaft drive assembly includes a stationary outer sheath and a rotatable interior drive shaft which is driven by an electric motor. Gear teeth of the pinion gear engage mating gear teeth formed on an upper surface of the rotary knife blade. Alternately, a pneumatic motor disposed in a throughbore of the handle assembly may be used to drive the pinion gear supported by the head assembly which, in turn, rotates the rotary knife blade.
Upon rotation of the pinion gear by the drive shaft of the flexible shaft drive assembly, the annular rotary blade rotates within the blade housing at a high RPM, on the order of 500-1500 RPM, depending on the structure and characteristics of the drive assembly including the motor, the shaft drive assembly, and a diameter and the number of gear teeth formed on the rotary knife blade. Conventional power operated rotary knives are disclosed in U.S. Pat. No. 6,354,949 to Baris et al., U.S. Pat. No. 6,751,872 to Whited et al., U.S. Pat. No. 6,769,184 to Whited, and U.S. Pat. No. 6,978,548 to Whited et al., all of which are assigned to the assignee of the present invention and all of which are incorporated herein in their respective entireties by reference.